Pentatonic and Whole Major/minor scales?

In Rock solos the most widely used scale is the Minor Pentatonic by far. Then the Major Pentatonic, the Major and Minor scales next.

That said, most guitarists will go outside the box on solos. Eric Clapton for instance is famous for switching between the Minor and Major Pentatonics in a solo, he is probably one of the best at this technique. It takes a real ear for music to pull this off well, not as easy as it would seem. The solo for Sunshine of Your Love is a great example as well as Badge.

http://www.youtube.com/watch?v=OY-LCDQl3Mg&feature=related

Here is a guy who does a good job on covering the solo from Badge, you can see him switching between the Minor and Major Pentatonic

http://www.youtube.com/watch?v=pqJfDFFQY5k

major, minor, major pentatonic and minor pentatonic scales are definitely the most common scales that are used in rock guitar solos. Typically, however the entire scale isn't necessarily used all the time, alot of players use licks or build little melodies based off these scales which might only contain 3 or 4 notes out of the scales.

Another common technique in blues and rock songs are the combination of scales: major pentatonic and minor pentatonic scales are often combined to create a bluesy sort of feeling. As well, alot of solos contain notes of a certain scale with chromatic notes from the chromatic scale.

A good idea would be to get some sheet music or TAB of your favorite rock guitar solos and analyse what they are doing, you'll learn alot that way.

Let's take the Am blues scale: A C D Eb E G
A blues-bar in A would use these chords A7, D7, E7. That means that over the E7 the 'B' note would sound well as it's part of the chord. The B note isnt part of the Am-penta scale, it's part of the A-minor scale. You'll find countless blues-artists playing 'chord' notes whether they are in the penta scale or not. So let's write down the chord notes:

A C# E G
D F# A C
E G# B D

Together with the Am-blues scale you get this 'full blues scale':
A B C C# D Eb E F# G G#

In other words, in the blues it's very easy to use all but two notes (here Bb and F), and even these can be used to great effect in chromatic runs. So use the penta scales as 'framework' but always feel free to use whatever notes outside that scale that sound good to you. :D

Thanks alot guys! Good info. I have to admit that i do like the flavor of the pent.s moreso than jamming an entire solo in the whole scale. In the future i'll key on being able to switch between scales and also "borrow" notes outside the frame.
One more question: how do arpeggios play into the equation?

Arpeggios are also used in solos, typically they are used to sort of outline chords, for example if you had a simple progression like: E major, A major, B major. You could play an E major arpeggio, A major arpeggio followed by the B major arpeggio. This is the one of the most simplest ways of using arpeggios in a lead, but you can combine arpeggios with scales just like you can combine different scales together.

For example, if you were playing a blues progression in E: you could play a few licks using the E minor pentatonic scale and then when the progression arrives at the B7, you could use a B major or B dominant 7 arpeggio. The important thing to realise is that for this type of playing you have to know the chords and the chord progression. An easier way to play arpeggios would be to use the key of the song: so if you're in E minor, you could choose to play an E minor scale for a couple of licks and then play a few lines using an E minor arpeggio.

I've always found that each scale you mentioned: Major, Minor, Pentatonic Major, Pentatonic Minor have their uses and situations where they sound best. Major sounds great, in my opinion, if you're looking for a very melodic or pop music type sound. Minor is very nice for a sadder tone. Pentatonic Major has a country/blues kind of flavor. Pentatonic Minor and the Blues scale are great for having a great blues sound.